Washington  - Canada's Foreign Minister Maxime Bernier has resigned Monday after he admitted to leaving sensitive government documents out in the open at a private residence, reported Canada television.

"This is a serious error," Prime Minister Stephen Harper said. "The minister has recognized this error himself and offered to resign."

The sensitive documents, which included classified information about NATO, were left behind at his ex-girlfriend's house earlier this year, according to CTV news.

Bernier has come under fire in recent weeks after it was reported that his ex-girlfriend, Julie Coulliard, 38, had previous relationships with men linked to organized crime.

Couillard was to appear on a Canadian television show Monday night to say that her former boyfriend was careless with classified documents.

Trade Minister David Emerson will take over Bernier's post on an interim basis. (dpa)